Monitoring Dampened BGP Routes

Purpose

Display information about dampened routes. Report whether the indirect next hop of a route is unreachable; if not, display the IGP cost to the indirect next hop.

The show ip bgp dampened-paths and show bgp ipv6 dampened-paths commands display similar information.

Action

To display information about dampened routes:

host1#show ip bgp dampened-paths
Local router ID 192.168.1.218, local AS 100
  Route flap dampening is enabled
  Decay half-life is 10 minutes while reachable, 20 minutes while unreachable
  Cuttoff threshold is 2000, reuse threshold is 750
  Maximum hold-down time is 20 minutes
  60 paths have active route flap histories (4560 bytes used)
  11 paths are suppressed
                                               Figure   Time until
Prefix          Peer      Status               of Merit Reuse/Remove
24.31.128.0/19   10.2.1.48 Suppressed/Reachable   2681    00:17:00
24.93.128.0/19   10.2.1.48 Suppressed/Reachable   2681    00:17:00
24.95.0.0/19     10.2.1.48 Suppressed/Reachable   2681    00:17:00
128.192.0.0/16   10.2.1.48 Available              1997    00:15:08
148.161.0.0/16   10.2.1.48 Available              1997    00:15:10
164.81.0.0/16    10.2.1.48 Available              1997    00:15:11
192.29.60.0/24   10.2.1.48 Available              1997    00:15:12
192.58.228.0/24  10.2.1.48 Available              1997    00:15:15
192.88.8.0/24    10.2.1.48 Available              1997    00:15:17
192.107.253.0/24 10.2.1.48 Suppressed/Unreachable 4331    00:19:42
192.195.44.0/24  10.2.1.48 Suppressed/Reachable   2923    00:19:15
192.195.49.0/24  10.2.1.48 Suppressed/Reachable   2923    00:19:15
192.195.50.0/24  10.2.1.48 Suppressed/Reachable   2923    00:19:15
192.197.150.0/24 10.2.1.48 Available              1997    00:15:25
192.222.89.0/24  10.2.1.48 Suppressed/Unreachable 2788    00:19:42
204.17.195.0/24  10.2.1.48 Suppressed/Reachable   2923    00:17:20
204.52.186.0/24  10.2.1.48 Available              1997    00:15:26
204.68.178.0/24  10.2.1.48 Available              1000    00:19:38
204.101.0.0/16   10.2.1.48 Available              1997    00:15:29
204.128.227.0/24 10.2.1.48 Suppressed/Reachable   2923    00:17:16
204.146.24.0/22  10.2.1.48 Available              1997    00:15:30
204.146.24.0/24  10.2.1.48 Available              1997    00:15:30

Meaning

Table 31 lists the show ip bgp dampened-paths command output fields.

Table 31: show ip bgp dampened-paths Output Fields

Field Name

Field Description

Local router ID

BGP router ID of the local router

local AS

Number of the local AS

Route flap dampening

Status of route flap dampening (enabled or disabled)

Decay half-life

Time (in minutes) after which a penalty is decreased. After the route has been assigned a penalty, the penalty is decreased by half after the half-life period (which is 15 minutes by default).

Cutoff threshold

Value of the penalty for a flapping route below which the route is unsuppressed

Reuse threshold

Time (in hours:minutes:seconds) after which the path will be made available

Maximum hold-down time

Interval, in seconds, after not receiving a keepalive message that the software declares a peer dead

route flap history

Status of route flap history for route paths

Prefix

Prefix for the IP address

Peer

IP address of BGP peer

Status

Status of route dampening of the route path

Figure of Merit

A measure of the route's stability. Higher values indicate more recent route flap activity or less stability.

Time until Reuse/Remove

Time until the route is either reused (if currently suppressed) or its history entry is removed (if currently available)

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